GMC
Good point and obviously one for discussion but common sense would suggest that for this additional scoring system, you would deem the official age of the bike by its model year or if modified with later components (deemed to be significant e.g. forks, motor, brakes etc.....) then the year would become the latter. So using your example, a 78 would in that case be deemed an 83 model.
Gippslander
If you read the proposal thoroughly, it does not replace anything but is an additional system, so the fast guys, young or old will still be fast & still pick up the silverware, no change. This idea is to encourage the 'others majority' who make up the numbers at meetings who typically finish in the slowest 66%. Events will be much healthier with full 40 starter grids than 10 or 12 etc. And as another example, if a young fast guy who just cant knock of the top 2 or 3 chooses to buy an 86 or 87 model bike rather than an 89 to compete with, then he/she still might get a podium over the line but gets a real good chance to win on handicap results.
Ted
This idea is in addition to not replacing anything. no one will be complaining about the fast guys winning, they would still be doing what they do best, that is not & will never be under threat.